One-Pot and Three-Component Condensation of Kojic Acid with Aromatic Aldehydes and Methyl Carbamate: Synthesis of Pyrano-1,3-Oxazine Derivatives in Aqueous Media

Abstract

A novel method for oxazine ring formation has been established using the reaction of kojic acid and aromatic aldehydes with methyl carbamate in the presence of p-toluenesulfonic acid in aqueous media to afford 4-aryl-6-hydroxymethyl-1,4-dihydropyrano[3,2-e][1,3] oxazine-2,8-diones in excellent yields. The present method does not involve any hazardous organic solvent. Therefore, this procedure could be classified as green chemistry.